Salton Sea Milk Vetch [Astragalus crotalariae (Benth.) Gray]

Salton Sea Milk Vetch [Astragalus crotalariae (Benth.) Gray]

Listing CNPS List 4 R-E-D Code 1-1-2

State/Federal. Status -- None FABACEAE Jan.-Apr.

Global Rank G4G5 State Rank S?

Distribution: San Diego County, Imperial County, and Riverside County; Arizona; Baja California, Mexico

Habitat: Barren, sandy locales in Sonoran Desert Scrub are the preferred habitat of Salton Sea Milk Vetch. Larrea divaricata ssp. tridentata, may be the dominant shrub within its habitat. Mild soil disturbance appears to enhance opportunities for this conspicuous annual/biennial.

Known Sites: Rare along the Borrego Salton Seaway, this species is easily identified by its vile odor. Because of its desolate habitat, it is difficult to assess the abundance of this milk vetch. An old report is from near Palm Spring. Herbarium collections include Fish Creek Wash at Split Mountain, Palo Verde Wash, Font's Point Wash, Carrizo Station, the Carrizo Badlands and South Mesa washes, and the historical Borrego Oil Well site. From Imperial County are herbarium collections at the entrance to the Salton Sea Naval Base, at S-22 near its junction with Highway 86, at Dixieland, and by Montgomery Road 1.1 miles west of Haley Road. Biological survey reports note sites northeast of the Fish Creek Mountains, as well as a number of locales north and southeast and south of the Superstition Hills, and southeast of the Superstition Mountains. Reported by Barneby from the head of the Salton Sea south to Carrizo Valley, southeast through Imperial County to the Yuma Desert in extreme southwestern Arizona, and south into Baja California (no collections are found for Baja at the herbarium of the San Diego Natural History Museum).

Status: The Salton Sea Milk Vetch is apparently stable in the southern deserts. Illegal off-road vehicle use negatively impacts this species.

Copyright May 1994 Craig H. Reiser.

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